device-buffer-length

Arguments: stream

Returns the desired length of buffers to be allocated for the stream, if any. This method may be called from almost anywhere (the exceptions are noted in the bulleted list below), and should return a value that is constant for each instance. The method may query the stream (to determine the optimum buffer length for the underlying device), and so the stream must exist before device-buffer-length methods are executed. Therefore, device-buffer-length methods must never be called by

• any before methods on device-open
• any methods on allocate-instance or initialize-instance,
• any methods on device-open, make-instance, or shared-initialize called before the most specific device-open primary method has had a chance to make the actual connection.

Defined methods

• On class: simple-stream: returns 4096.
• On class: null-simple-stream: returns 256.

See streams.htm for information on the simple-streams implementation in Allegro CL. The older but still supported Gray streams implementation is described in gray-streams.htm.

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This page was not revised from the 8.1 page.
Created 2010.1.21.